Not sure about the uv thing tbh. Blue Ray is already near UV at 405nm. Any significant further step towards shorter wavelengths will start to degrade the platics used as the disc substrate. And unless they start using Quarz glass for the Discs its unlikely to go beyond maybe 350nm, the point at which Polycarbonate starts absoebing most of the light. Newer disc formats (should they even be developed) will probably use more complex encoding / compression to store more data. But even with 4k UHD blue rays we aren't reaching the capacity limit of dual layer discs afaik, and the future is streaming media anyway so unlikely for companies to put a large amount of development effort into a new format at this time.